Nanometric robots controlled by a magnetic field can kill bacteria in dentinal tubules and increase the success rate of root canal treatment, according to researchers from the Indian Institute of Science (IISc) and Tranautilus, a company affiliated with IISc.
Root canal treatment is routinely performed to treat dental infections in millions of patients. The procedure involves removing the infected soft tissue from the tooth, known as the pulp, and flushing the tooth with antibiotics and chemicals to kill the bacteria causing the infection. However, this treatment often does not completely eliminate bacteria (especially antibiotic-resistant bacteria, such as Enterococcus faecalis) that hide in the microscopic grooves of the tooth called dentinal tubules.
“Root canals are very small, and the bacteria live deep in the tissues. Current technology cannot penetrate deep enough to kill them,” explains Shanmukh Srinivas, a researcher at the Centre for Nanoscience and Engineering (CeNSE) at IISc and co-founder of Theranautilus.
The team has now developed spiral-shaped nanorobots made of iron-coated silica that can be controlled by a device generating low-intensity magnetic fields (Advanced Healthcare Materials). They inserted these nanorobots into a sample of extracted teeth and tracked their movement under a microscope.
“By adjusting the frequency of the magnetic field, they were able to move the nanorobots randomly and allow them to penetrate deep into the dentinal tubules. They can also be removed from the patient’s teeth,” says Srinivas.
NO OTHER TECHNOLOGY CAN DO THIS
“Essentially, the magnetic field can be manipulated to generate heat on the surface of the nanorobot, killing nearby bacteria,” says Debayan Dasgupta, a researcher at CeNSE and co-founder of Theranautilus. “No other technology on the market today can do this.”
Traditionally, to enhance the effectiveness of root canal treatment, shock waves were introduced into the fluid via ultrasound or laser pulses to remove bacteria and tissue debris. However, these pulses only penetrate to a depth of about 800 micrometers, and their energy dissipates quickly. As a result, the nanorobots were able to penetrate even deeper, up to 2000 micrometers. The researchers also said that using heat to kill bacteria is a safer alternative to chemicals and antibiotics.
Theranautilus is the result of several years of research on magnetically controlled nanoparticles conducted in Professor Ambarish Ghosh’s lab at CeNSE. Along with his colleagues, his group has already demonstrated that these nanoparticles use light to trap and move objects, float in blood and living cells, and firmly attach to cancer cells. “These studies have shown that they are safe for use in living tissues,” says Dasgupta.
The research team tested the dental nanorobots in a mouse model and found that they were safe and effective. They are also working on a new type of medical device that can be easily carried in the mouth, allowing dentists to insert and manipulate nanobots inside teeth during root canal treatment.
Ghosh says, “The clinical application of this technology, which was considered futuristic just three years ago, is now around the corner. It’s exciting to see simple scientific curiosity turn into a medical intervention that could impact millions of people in India alone.”